Recently the Brazilian authorities formed a special task force to locate and shut down sweatshops.

Many of the workers are smuggled into Brazil from Bolivia, said Luiz Alexandre Faria from the labour ministry.

"They can't leave the workshop until they pay for their journey. Some employers even confiscate the workers' documents," he told the BBC.

Brazil's criminal code classifies slave-like labour as instances including when a person is forced to work exhausting hours, subjected to an unsafe working environment and prevented or restricted in their movement to and from work.